Back in 2015, Microsoft announced that it was bringing over 100 Xbox 360 games to the Xbox One console. A new backwards compatibility program fundamentally shifting how we perceived consoles and inter-generational game libraries through the impressive technical feat of making two very different pieces of hardware play nice through emulation and innovation. And in the process, the team at Xbox made the whole thing look seamless -- inevitable even.

It’s a line of thinking that has been with Microsoft for a while too, going as far back as the launch of the Xbox 360 which supported a selection of original Xbox titles at launch. That feeling of moving forward with a library intact, it’s something the team holds dear. As Jason Ronald, Director of Program Management for Xbox Series X|S tells me, “preservation is core to our DNA”.

Behind the scenes of course it’s a combination of technical wizardry, figuring out legalities, extensive testing and working closely with partners, publishers, and developers. Over the lifespan of the Xbox One the backwards compatibility initiative evolved, enhancing titles for the mid-generation Xbox One X refresh led to enhanced resolution and rendering as the team consistently added more and more titles.

The Next-Gen Arrival

---

Fast forward to the launch of the Xbox Series S and Xbox Series X, and an entire generation of Xbox One games and interactive experiences arrived alongside the next-gen Xbox consoles.

“We believe in backwards compatibility and this notion of game preservation, and we're proud of what we were able to do with the last generation of consoles,” Jason continues. “As we started development on the Xbox Series X and S, compatibility was a critical tenet from day one. It was important that all the games that you were able to play on the Xbox One generation were available.”

---

“We believe in backwards compatibility and this notion of game preservation, and we're proud of what we were able to do with the last generation of consoles.”

---

Backwards compatibility is more than simply flicking a switch. Getting the entire Xbox One library there at launch required hundreds of thousands of hours of testing, validation, and collaborating with developers and publishers for things like licensing and rights. And that’s testing in the ‘play the entire game’ sense too, which has seen a [technical] toolset and the skills to play these games within the team improve over the years.

As this preservation became core to Xbox DNA, so too did it become a part of the development of next-gen hardware.

Far Cry 4, with FPS Boost now runs at 60 frames-per-second on next-gen Xbox.
“I think it's probably even harder than most people think,” Jason explains when asked about the underlying effort involved. “When we were designing the Series X and the Series S this commitment to compatibility influenced the design of the silicon, the hardware, and it has impacted the design of the operating system too. The hundreds of thousands of hours the team puts in, hopefully that shows the commitment and the belief we have at Microsoft and Xbox -- in the notion that your game catalogue should move with you.”

Even though the backwards compatibility team took a well deserved break after the launch of the new consoles it was still cooking up something new. “A lot of times the community, and we do it internally too, we say the backwards compatibility team is made up of a bunch of magicians and wizards,” Jason adds jovially. “One of my favourite things is when the team pings me and they're, like, ‘we just got this awesome thing working’. Over the many years that we've been working on this programme, the team has really learnt a lot -- the different behaviours of titles, the different ways that game engines work. It’s that knowledge that enables innovations like FPS Boost to happen.”

FPS Boost - Playing With Power

---

Naturally, new hardware means more powerful CPUs, GPUs, and storage to leverage -- a fact that has already seen many titles load faster, run at higher resolutions, and perform better simply by firing them up on an Xbox Series X or S.

“We really designed the Series X to run all games at 4K, at 60 frames-per-second,” Jason explains. “With the Xbox One generation, some titles were able to hit 30 frames-per-second and some 60. We really believe best in class gaming experiences lean into things like higher frame-rates, buttery-smooth input... that was a design target as we designed the system.

---

“When we were designing the Series X and the Series S this commitment to compatibility influenced the design of the silicon, the hardware, and it has impacted the design of the operating system too.”

---

“When it came to backwards compatibility as we started getting these games up, we realised that with all this extra processing power that we have with the Xbox Series X and the Series S, games were in many cases “waiting”,” Jason continues. “The hardware would process a frame in dramatically less time than before. That was a fascinating insight – so we got to thinking, what would happen if we actually got the title to render more quickly?”

Related: Xbox Backwards Compatibility Sees Titles Gets a Sizeable FPS Boost

---

Without getting into pure technical detail each frame rendered for a game takes a certain amount of time (measured in ms) based on hardware capabilities. And that frame-time plays into the overall end result -- be it a locked 30 frames-per-second or something higher. The “waiting” refers to the Xbox Series X being able to dramatically reduce the time it takes to render a frame.

Watch Dogs 2, another classic given the FPS Boost treatment.
“We realised that we could come up with a technique that would actually allow us to effectively double the frame rate of these titles at the system level,” Jason recalls, pointing to the eureka moment that led to a new feature called FPS Boost. “The technique doesn't work on all titles, a lot of it depends on how the game was originally written. During testing we’ve had some titles where the game would play perfectly fine but then suddenly, we'd realise that characters were animating twice as fast.”

Another example saw a game’s physics system break entirely, as it was tied to the sort of internal timings that make FPS Boost possible. “That's why we're doing a lot of testing,” Jason adds. “What we don't want is the first third of the game working perfectly and then you get to the second two thirds and discover all these game-breaking bugs. And we're also providing them to the publisher and the original developers to make sure we're really adhering to the original artistic intent they had. When we release these titles, that means we and the publishers are fully on board with the idea."

“To see their games look and play better than they've ever seen them, with no additional work from them, it's a very easy conversation to have.”

Preserving History

---

There’s a key aspect of backwards compatibility that sits alongside the ability to bring your library across to a new generation of Xbox hardware, and leveraging that to improve the look and feel. Or, to ensure that a service like Xbox Game Pass can continue to grow from strength to strength. That aspect is history -- the ability to actually play a title that might otherwise be lost to time.

So even though playing an older title like Sniper Elite 4 with FPS Boost is smoother, and arguably better -- the team is still looking to make it something that can be toggled on or off. This not only adds choice, but is tied to the very idea of preserving videogame history.

---

“ When we release these titles, that means we and the publishers are fully on board with the idea. To see their games look and play better than they've ever seen them, with no additional work from them, it's a very easy conversation to have.”

---

“We listen to and learn from the community and see how they play these games,” Jason enthuses. “There are some people that want to play the game exactly as it was originally intended by developers. We're going to release a system update that allows a player to choose on a per game basis whether or not to enable Auto HDR or FPS Boost.”

As with anything that looks back, there are issues outside of simply getting a game to run. A separate but apt example is the recent leak of a Goldeneye 007 Nintendo 64 remake for the Xbox 360 -- according to reports, trying to obtain the rights to the classic actually led to its cancellation.


“A lot of the challenges we also run into are rights issues or licencing issues,” Jason confirms, noting that the further back in time the team goes the more difficult this side becomes. “Even if we can technically get the game working, maybe the developer doesn't exist anymore, or maybe the song rights have expired. It's a multi-dimensional challenge between technology, legal challenges and business considerations. We do everything that we can to bring as many games as possible forward.”

As backwards compatibility (in this setting) refers to previous generations of Xbox consoles, there’s also a possibility where different systems like, say, the Sega Dreamcast could be emulated in a similar fashion. Interestingly, instead of a flat-out no -- we got the sort of response that reinforces the overall ideal of preservation. Something that transcends what one specific platform might support -- it’s about the games.

“The team has definitely had some ideas,” Jason adds in conclusion when asked about applying expertise beyond previous generations of Xbox consoles. “We've had [Xbox] games that we got working and we just couldn't get the right approvals to actually release. Ultimately it depends on the game, and every game is interesting. The team has found that certain kinds of titles are going to be more challenging than others, whether that's a technical issue or a licencing issue. But that doesn't mean that we won’t try – preservation is core to our DNA now.”